The invention relates to a method for the manufacture of tubular bags, which are subsequently fastened on a strip in such a manner that they are arranged partially overlapped one on top of the other. The invention relates further more to an apparatus for the manufacture of the bags and to their above-described arrangement.
When manufacturing tubular bags, the initially flat foil is pulled off from a roll, is guided over a forming shoulder and is shaped into a plastic tube with a longitudinal lap joint, which in turn encloses a fill pipe adapted to its shape. After the longitudinal joint has been sealed into a longitudinal seam, a bottom seam is produced with a first cross-sealing device. When the tubular bag is filled through the fill pipe, its closing occurs through a top seam created with a second cross-sealing device, whereby at the same time the bottom seam for the next following plastic tube is sealed.
New avenues for sales and changing demands by the consumer require continuously innovative sales methods and thus consequently new forms for packaging. The tubular bag shows here multiple possibilities for variations, whereby both in economical and ecological respects a material-saving handling of the packaging material is guaranteed.
A form of packaging is known from the state of the art in which the tubular bag is moved onto one individual, suitably designed or onto a curved rod. Usually a suitable punch-out is for this purpose provided in the top seam, which punch-out is either only circular or has in addition a slot on both sides. The respective tool for the last-mentioned design is known to the man skilled in the art as the Eurohole punch.
Furthermore a form of packaging is known in which, in order to hang and present the packages, a hanger strip, for example of cardboard, is used. The strip has on the one hand a punch-out for facilitating a hanging onto sales posts and on the other hand a certain number of further punch-outs in order to receive the bags. The top seam of the respective bag is hereby placed into the associated punch-out so that a fixation through clamping occurs. The distances between the bags or the punch-outs can be chosen such that these rest partially in their length one on top of the other. A scale-like arrangement of the packages is achieved in this manner. Furthermore a relatively high package density is obtained, whereby the presentation with the complete printing on the front side of such bag is guaranteed as the consumer removes the sequence of bags from the hanger strip.
Packages of the above-described type are preferably utilized for products like snack foods (potato chips, peanuts) or sweets. The form of packaging is suited ideally for use in stores with special displays as, for example, gas-station shops.
The packages are manufactured according to the state of the art as follows: The products are packaged on a tubular-bagging machine. Machines of this type are sufficiently described in the technical literature and have been on the market for many decades. A description is therefore not needed.
The hanger strip is manually removed from the delivery bundle.
The bags are now also manually one after the other placed with the top seam into the provided punch-outs.
The hanger strip can subsequently be placed with the inserted bags into a transport package, whereby also this method step is generally carried out manually.
This method is disadvantageous since the manual work results in high employee expenses, which make the package unnecessarily more expensive. Furthermore no reproducible quality can be created so that again and again packages are insufficiently inserted into the box and can fall off the latest when being hung onto the display post. A total loss of the package must then be expected in the provided sales areas.
For this reason it is being tried again and again to automate this packaging process. It is hereby being tried to position the bags manufactured on the tubular-bagging machine by means of suitable sorting and grouping devices in such a manner that the above-described hanger strip can be fastened on the bag. This process has the disadvantage that a bag, after it was released after its manufacture, is almost impossible to position exactly. The fixing process thus demands a very high technical and mechanical expertise, which is in no relationship to the production safety.
The present invention has therefore the purpose to overcome the afore-described disadvantages during the manufacture of the afore-described packaging form and to enable with simple means an automatic manufacture with little expense.
The purpose is attained according to the invention by the bag filled with the product being, after the formation of the first closing seam, subjected to a second method step during which, after the advance of one bag length, the second closing seam is formed, while at the same time a hanger strip is fastened on the first closing seam.
Further characteristics of the invention are contained in the subclaims.
The invention does not only eliminate the earlier discussed deficiencies of the state of the art. Instead an enormous potential for increase of the production with an extremely low expense in investment results from this for the user.
A particular characteristic of the invention is that the mounting of the hanging strip occurs already during the bag-manufacturing process. The advantage of this is that the bag is practically fixed in this phase so that the mounting of the strip is possible through simple means. Furthermore a packaging sequence free of any interference is guaranteed only in this manner.
The hanger strips are also supplied automatically. The strip can be made, for example, of a cardboard material or of a plastic foil. It is furthermore possible that the strips are taken in a customized length from a magazine and are fed to the manufacturing process, or are pulled off from a roll and are automatically cut off after a preselected length.
Many possibilities exist for mounting the bags on the hanger strip, whereby only a few will be mentioned here. When the strip has a sealing layer the connection to the bag can occur through hot sealing. With suitably chosen materials a welding is also conceivable. A further possibility is to use an adhesive (for example hotmelt) so that a connection is subsequently created by contact pressure. Also a fixation by means of clamps or by clamping is possible with the help of suitable devices.
The sales-enhancing and space-saving scale-like arrangement can be achieved by making the distances between the bag fixation locations on the hanger strip less than the bag length. The method of the invention and also the corresponding apparatus guarantee that here too the representative bag front side faces the viewer. This means in turn that the back side of the bag with the longitudinal seam is covered by the hanger strip. By suitably adjusting the advance of the hanger strip it is also possible to adjust the overlapping of the respective bags. When various distances are needed for the respective package types or products, then the adjustment of the advance can also occur automatically. A pressure mark can, for example, be provided on the hanger strip, which is registered by a suitable recognizing apparatus. In this manner it is also possible to automatically adjust the number of attached bags and the hanger strip can be cut off at the suitable spot.
The bags are in an advantageous embodiment fastened xe2x80x9coverheadxe2x80x9d on the hanger strips. After the second seam has been formed, the closed bag is separated in the sealing station from the next package by means of a separating knife. The bag tilts now forwardly at 180xc2x0. It is in addition conceivable that this tilting is passively or actively supported by a device. For example, metal guides or a blowing device are mentioned here. This method step has now the advantage that the face of the bag carrying the advertisement shows in front and the longitudinal seam is, as desired, covered by the hanger strip. It is furthermore possible to use during the release of the bag, if the strip was sealed or welded on, the so-called peel effect. The bag can in this manner be released from the strip with relatively little force.
The invention will be discussed in greater detail hereinafter in connection with one exemplary embodiment and the drawings, in which:
FIG. 1 illustrates a bag package with hanger strip, as it is known from the state of the art.
FIG. 2 illustrates an apparatus, with the help of which such a package is automatically packaged according to the invention.
FIG. 3 illustrates an apparatus similar to the apparatus of FIG. 2, except that the second station applies an adhesive.
FIG. 4 illustrates an apparatus similar to the apparatus of FIG. 2, except that the second station has a clamping function.